1. Detection Methodology: ClamAV primarily relies on signature-based detection, comparing scanned files against a database of known malware signatures, while NTFS Security Manager uses behavior-based detection to identify threats based on unusual file activities and suspicious behavior.
2. Supported Platforms: ClamAV is compatible with various operating systems including Linux, macOS, and Windows, whereas NTFS Security Manager is specifically designed for Windows-based systems to manage access control and permissions on NTFS file systems.
3. Real-time Protection: ClamAV lacks real-time protection capabilities, requiring manual scanning of files or periodic schedule scans, whereas NTFS Security Manager provides real-time monitoring and protection, instantly identifying and mitigating security risks on the filesystem.
4. Features: ClamAV offers basic antivirus functionalities such as malware scanning and removal, while NTFS Security Manager includes advanced features like file auditing, permissions management, and directory quota control to enhance security and governance.
5. Scalability: ClamAV's performance may degrade with a large number of files due to its resource-intensive scanning process, whereas NTFS Security Manager's efficient design allows for scalability and management of extensive file systems without compromising system performance.

In Summary, the key differences between ClamAV and NTFS Security Manager lie in their detection methodology, supported platforms, real-time protection, features, and scalability.